For decades, the suburbs of Long Island have been perceived as a political safe haven for members of the Republican Party. The Grand Old Party dominated the Island, hosting a sold-out campaign rally at Nassau Coliseum for President Richard Nixon in 1972 and then, eight years later, helping a virtually unknown Town of Hempstead supervisor by the name of Alfonse D’Amato get elected to the U.S. Senate.

But as the demographics on Long Island have changed, so has voter registration, and as of July 1, Long Island has officially become Democratic.

Nassau County has been feeling the effects of the demographic shift for some time. Suburbs not only in New York but across the country are seeing the “liberal swing,” as increasing numbers of minorities and immigrants move from urban areas into the suburbs. These groups tend to lean left. As a result, there are two new registered Democratic voters on Long Island for every one Republican.

According to a recent New York Times article entitled, “In Nassau County, an Influx of Democrats Threatens a G.O.P. Stronghold,” if you compare current voter registration numbers to those from a decade ago, there are nearly 82,000 more registered Democrats in the county, while there are more than 16,000 fewer Republicans.

It took a little longer for Suffolk County to feel the effects of the demographic shift, but as of July 1, there were 304,114 registered Democratic voters and 303,728 registered Republicans, giving Democrats a 386-vote edge.

Although they’re now outnumbered, Republicans have still managed major local victories. They hold a 10-to-9 majority in the Nassau County Legislature. In addition, the GOP holds all five State Senate seats representing Nassau, and County Executive Ed Mangano is a Republican.

Mangano managed to defeat Democratic incumbent Tom Suozzi by 386 votes in 2009. Suozzi was just the second Democrat elected Nassau County executive since 1938. In November, the two will have a political rematch.